Lamp-socket rheostat



March 18, 193 0: c. 1... WEICHELT 1,750,739

LAMP SOCKET RHEOSTAT Filed March 29 1926 i; A TTbRNEY.

Patented Mar. 18, 1930 TEES CARL L. \VEICI-IELIZ, F PHILADELPHIA, PENNSYLVANIA, .ASSIGNOR TO WIRT COM- PANY, OF PHILADELPHIA, PENNSYLVANIA, A CGRPORATION 0F MAINE LAMP-SOCKET RI-IEOSTAT Application filed March 29, 1826. Serial No. 98,170.

This invention relates to attachments for incandescent lamps by means of which the flow of current to the filament may be regulated andthe intensity or candle power of the lightproduced thereby controlled and it has for an object to provide a device of this character appropriate particularly for use with fixtures in which a lamp socket is enclosed within an ornamental protecting jacket member which may be secured to any suitable support or which may comprise part of a lighting fixture.

The invention is directed more particularly to providing a current reducing device including a lamp socket and a rheostat fixed in axial alinement thereto, said parts being of approximately the same diameter whereby they may be inserted longitudinally in a tubular member of a fixture which has an interior diameter suflicient to receive the socket proper.

A further feature of the invention is the provision of a sliding contact arrangement which insures the maintenance of a positive and efficient engagement of the stationary by the moving contacts.

Briefly these objects are accomplished by an arrangement of parts in which a tubular rheostat ring is connected in axial alinement with a lamp socket and a rotatable shaft extends axially through the ring and carries a spring contact adapted to engage the rheo stat terminals and the center cont-act of a lamp socket simultaneously.

To these and other ends th invention comprises further improvements which will be more thoroughly understood with the aid of the following description, the novel features being pointed out in the appended claims.

In the drawings:

Fig. 1 is a view partly in elevation and partly in section of a dimmer or current reducer illustrating one embodiment of the invention.

Fig. 2 is a vertical central sectional view of the dimmer with the enclosing acket and the lower operating knob removed. taken along the plane indicated by the line 2* x of Fig. 1.

Fig. 3 is a similar vertical sectional view taken at right angles to Fig. 2 as indicated by the line 3"3".

Figs. 4, and 6 are cross sectional views of the complete device looking downwardly on the planes indicated by the lines P -4:"; 5 5 and (i -6 respectively of Figs. 2 and 3.

Fig. 7 is a fragmentary view in elevation of the switch shaft and brush and of the sleeve within which the shaft rotates.

Similar reference characters in the several figures indicate similar parts.

In the drawings, I have shown an electrical fixture of a type with which a device embodying my invention is particularly adapted to be used, comprising a tubular jacket 8 and its supporting member 9 composed of a molded or baked insulating material such as porcelain. The parts to which the present invention is directed comprise the electric lamp socket 10 and the associated dimmer 11 removably mounted in, but rigidly secured to, the jacket 8. The lamp socket may be the standard screw-threaded shell 10 which I have mounted. on an in sulating disc 12. The latter carries on its opposite faces a pair of spring contacts 15 and 16 secured by the rivet 14. The contact 15 extends within the socket 10 for engagement with the end or center terminal of a lamp inserted in the socket and the contact 16 cooperates with the switch arm of the associated dimmer.

In the general form of device to which the invention relates, the desired current reduction is produced by the use of a fixed rheostat having terminals adapted to be successively engaged by a moving contact or wiper to complete a series circuit including a source of potential and the lamp filament. In the present embodiment of my invention, I have shown the rheostat as a tubular ring composed of inner and outer shells 17 and 18 enclosing a resistance coil 19 embedded in a mass of insulating material 20 and carrying terminals 21, 22 and 23, exposed at the upper end and a terminal 2& projecting downward- 1y at the lower end of the ring. The latter is preferably closed at its lower end by a layer of insulation 20. It is likewise closed at its upper end by securing thereto shell 10 and its insulator 12 by means of downwardly extending ears 25 on the latter which are held in place by the rivets 13 and screws 26.

5 In this manner, there is provided an arrangement of parts in which the rheostat may be readily and rigidly secured in axial alinement with and to the socket and in which the shells of the socket and rheostat may be rigidly connected in circuit with each other.

In accordance with a feature of the pre ent invention, the movable contact arrangement is one adapted to engage the center contact 16 while successively engaging the rheostat terminals 21, 22 and 23, and thereby complete a series circuit through the rheostat and the lamp socket from a source of current to a lamp filament. Referring particularly to Figs. 2, 3, 6 and 7, I have shown a tubular sleeve 27 extending axially within the rheostat ring and having its lower'end threaded and provided with lock nuts 28 and 29 by means ofwhich it is rigidly connected to the insulated bottom 20 of the rheostat. This member 27 serves as a bushing or bearing for a switch shaft 33 carrying at its upper end a spring contact 34 and on its other end a key or knob 35 secured through the media of screw 36 threaded into the shaft end.

The contact 34 may be of any desired form adapted to provide a connection between the center contact 16 and the rheostat contacts 21, 22 and 23. In the form shown, the switch contact 34 is in the form of a spring finger extending horizontally, or in a direction transverse, to the shaft. The latter is provided with a flat head 33 carrying two pieces of insulating material 37 and 38 between whichthe fixed end of the spring is engaged. The head 33 is preferably rectangular in shape and at opposite sides is provided with two lugs or cars 39 that are bent over said insulating pieces to rigidly secure them. The body of the spring 34 is bent in a U shape so as to overlie the head thus providing a center portion for engagement with the center contact 16 and a free end or shoewhich may be offset slightly to properly position it with respect to the rheostat terminals 21, 22 and 23.

The enlarged head 33 on the shaft bears against the upper end of the guide tube or sleeve 27 and in order to limit the rotary movement of the head the end'of the tube, atone side, is cut away as indicated at 42 in Figs. 3 and 7, to provide two shoulders with which a pin 40 in the shaft will engage to limit the rotation of the shaft in both directions. To facilitate assembling the parts, the pin 40 has a head 41 fitting into a counter-sink in the shaft in which it is held after assembly by the inner wall of the projecting portion 42 of'the sleeve. 7

lVhen an electric fixture of the general t e shown in the drawin s is em lo ed it .71 e P I) between each individual turn of wire.

is usually customary to provide the connection between the lamp socket 10 and the mainplished by extending the sleeve 27 secured V to the'dimmer 11, through the bottom of the a-cket wall and threadin thereon a Jair of .i 23

lock nuts, 30 and 45, adapted to engage the inner and outer walls of the jacket end respectively. To insure the maintenance of the desired position of the nut 30 on the sleeve 27 and therefore the correct location of the socket relative to the jacket, a spacing washer'32 is inserted between the nuts 29 and 30.

The lead-in wires 43 and 44 are secured at one end to the house wiring circuit and their other ends are joined to terminals 48 and 49, connected respectively to rheostat terminals 24 and the outer shell 18 of the rheostat.

The construction of the resistance coil or ring 19 per se may assume various forms and a form which has been found especially satisfactorily is the one disclosed in my copending application Serial No. 98,171 filed concurrently herewith. Briefly, it comprises a number of contact bars three being shown as 21, 22 and 23, arrangedin alinement concentric to the axis of the ring with their upper ends exposed, one contact bar as 24 arranged in a similar manner with its lower end exposed and resistance coils wound cylindrically upon the bars with insulating layers separating the coils and bars and interposed The opposite ends of successive coils are secured to the same contact bar or terminal'and the free ends of theinitial and final coils are then bound to separate bars. The terminal 24 and one of the other terminals as 23,

a portion of the resistance unit to contact 34 and thence to center contact 16. Since the center contact 16 is secured through rivet 14 to spring contact 15, current then passes through the end terminal, the filament and the sheath of the lamp to the socket shell 10 and thence through rivets 13, ears 25, screws 26, rheostat shell 18, to terminal 49 and lead-in wire 44, thereby comple ing a circuit including in series a resistance and the lamp filament. By rotating the shaft to cause the contact 3 1 to engage the terminal 23, the resistance unit will be short-circuited and the lamp will burn with full brilliancy.

From the arrangements of parts described, it will be seen that the device comprises a simple construction in which the various members are maintained in rigid mechanical and electrical contact with each other, in which the switching member may be easily rotated to produce a firm positive engagement of the stationary contacts by the rotating contact and in which the socket and dimmer maybe readily detached from the fixture jacket with which it is associated.

In accordance with the provisions of the patent statutes the principle of the invention has been described, together with the apparatus which is now considered to represent the best embodiment thereof, but it is de sired to have it understood that the apparatus shown is merely illustrative, and that the invention may be carried out in other ways.

The invention having been described, what is claimed as new and desired to be secured by Letters Patent, is as follows:

1. A current reducer for electric lamps comprising a socket embodying a shell portion mounted on an insulating disc carrying on its opposite faces a pair of joined center contacts, a rheostat ring associated with the socket and including an outer shell connected thereto, and having internally disposed re sistance windings provided with circularly disposed terminals at one end of the ring, a rotary brush engaging one of the center contacts and adapted to successively cooperate with the rheostat terminals while in contact with said center contact.

2. A current reducer for electric lamps comprising a socket for receiving a lamp having a center contact, a stationary rheostat ring in axial alinement with said socket embodying an outer conductive shell mechanically and electrically connected to the socket and a plurality of resistance windings insulated from the shell. having terminals disposed circularly at the upper end of the ring and a lead-in terminal for the windings disposed on the lower end of the ring, a switching shaft associated with the rheostat and carrying a brush adapted to engage the upper terminals upon relative rotation of the shaft and ring and providing electrical connection to the center contact, and binding posts joined to the lower terminal and to the rheostat outer shell whereby the device may be connected to a source of current.

3. A current reducer for electric lamps comprising a socket shell mounted on an insulating disc, a center contact thereon, a tubular rheostat ring of substantially the same external diameter as that of the shell closed at one end and at its open end mechanically connected to the insulating disc and elec trically connected to the socket shell, said ring including successively disposed resistance coils each provided with a separate terminal, a sleeve rigidly mounted in the rheostat rin having a cut-out portion at its upper end providing spaced shoulders, a shaft within the sleeve, a projection on the shaft cooperating with the shoulders to limit the movement oi" the shaft and a brush carried by the latter and adapted to engage the center contact of the socket and the resistance terminals.

4. in a lamp fixture, the combination with a tubular jacket closed at one end, of a current reducing device within the acket comprising a -amp socket, and a rheostat ring embodying a resstance and secured at one end in the axis of ti e socket, a spring contact in oer adapted to provide electrical conne tion to the center contact of a lamp, a tubular sleeve extending through the ring and the acket, a switching shaft or M irough and rotatable within the sleeve, and a brush contact on the shaft engaging said member and cooperating with the resistance winding, while in contact with said. member.

5. l i current reducer, the combination with posed axially thereoi comprising a shell containing a resistance element having a plurality of terminals, of an insulating member located between the shell and socket securing devices extending through the insulator nd connecting said parts, a center lamp contact and a spring center contact electrically connected and lying atcpposite sides of the insulator, a spring switch member engaging the spring contact which provides pressure thereon and adapted to successively engage the resistance element terminals while in contact with said center contact, and an actuating shaft connected to said switch extending centrally and longitudinally of the rheostat for oscillating said switch member.

6. A current reducer for electric lamp fixtures comprising a lamp socket shell mounted on an insulating disc, a rheostat ring of corresponding diameter mounted on the opposite side or the disc comprising an outer conducting shell containing a plurality of resistance windings carrying terminals at the end nearest to said disc, securing devices extending through said disc for mechanically and electrically connecting said ring and shell, a switch arm co-operating with the re sistance terminals, means to actuate said switching arm and a spring member mounted on said disc and adapted to provide electrical connection to both the center cont-act lamp socket, a rheostat member dies of alamp and to the switching arm, said member establishing positive engagement of the switch with the resistance terminals.

7. A current regulator for electric lamps comprising a lamp socket shell, a spring contact member adapted to provide electrical connection to the center contact of a lamp, a tubular rheostat ring electrically secured at one end to the shell and containing a plurality of resistance coils provided with circularly disposed terminals at the end nearest to the shell, a switching arm rotatable in the axis of the ring cooperating with said terminals and said contact member which provides pressure on and electrical connection to the arm, and an actuating shaft connected to the arm and extending longitudinally or" the rheostat.

8. In a regulator for electric lamps, the

' combination with a lamp socket, and a rheostat of corresponding diameter disposed axially of the socket comprising an outer conducting shell and a resistance element naving a plurality of terminals, of an insulating member arranged between and serving to mechanically connect the socket and the rheostat outer shell, means securing said shell and resistance element to the insulating member and electrically connecting them, spring center'contacts mounted on opposite faces of the insulator, a switch member engaging one of said center contacts with the upper end of the rheostat and capable of rotation into and out of engagement with the rheostat terminals, said last mentioned contact establishing positive engagement of the switch with the resistance terminals, circuit connections extending from the bottom of the rheostat leading to the resistance element and the rheostat shell and means supported at the bottom of the rheostat for operating the switch member. 7

This specification signed this 25th day of March, 1926.

CARL L. WEIGHELT. 

